fffdddooo
Newbie level 1
Using an attenuator pasive probe with a spectrum analizer
Hi.
I have find **broken link removed** wich suggest the use of a passive probe in 1:10 to attenuate the signal to a spectrum analyser in order to be able to use signals above +20dBm.
The theory is easy, the 9M resistance is a voltage divider with the 50ohm internal resistance of the analiser so it will attenuate a lot. So let's see: I have a tektronix 1:10 probe like this one, with 9M and 17pF
**broken link removed**
The attenuation will be 9M/50 = 180000 = 105dB.
The problem I see is the capacitor, at DC the attenuation is OK, but when frequency grows the impedance of the capacitor decreases and the voltage divider stops working. For example at 150Khz Zc=62K then 62K/50= 62dB and at 433Mhz Zc=21ohm so the attenuator will be not working at all.
Am I wrong?
Hi.
I have find **broken link removed** wich suggest the use of a passive probe in 1:10 to attenuate the signal to a spectrum analyser in order to be able to use signals above +20dBm.
The theory is easy, the 9M resistance is a voltage divider with the 50ohm internal resistance of the analiser so it will attenuate a lot. So let's see: I have a tektronix 1:10 probe like this one, with 9M and 17pF
**broken link removed**
The attenuation will be 9M/50 = 180000 = 105dB.
The problem I see is the capacitor, at DC the attenuation is OK, but when frequency grows the impedance of the capacitor decreases and the voltage divider stops working. For example at 150Khz Zc=62K then 62K/50= 62dB and at 433Mhz Zc=21ohm so the attenuator will be not working at all.
Am I wrong?